The aim of the work was to elaborate the chromatographic conditions enabling the separation and detection of fumaric acid and maleic acid. It was found that the best chromatographic separation is possible on chromatographic plates covered with silica gel using an ethanol – ammonia – water mobile phase in a volume ratio of 6: 1: 1. Methyl red and eosin yellow enable the detection of analyzed acids. An acidindicator system is formed, which is active in UV light (λmax = 215 nm), which enables densitometric analysis of acids. Used visualizing reagents create possibilities of identification for fumaric and maleic acid on a thin layer. The developed conditions for chromatographic separation and detection of maleic acid and fumaric acid are of great importance in their pharmaceutical analysis.

Keywords: fumaric acid, maleic acid, TLC, separation, detection, densitometry, spectrodensitometry, identification.